Messages in this thread | | | From | Dmitry Vyukov <> | Date | Wed, 26 May 2021 09:00:35 +0200 | Subject | Re: [syzbot] WARNING in ex_handler_fprestore |
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On Wed, May 26, 2021 at 2:33 AM Andy Lutomirski <luto@kernel.org> wrote: > > On 5/24/21 1:51 AM, syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 45af60e7 Merge tag 'for-5.13-rc2-tag' of git://git.kernel... > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1591e9f7d00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=18fade5827eb74f7 > > dashboard link: https://syzkaller.appspot.com/bug?extid=2067e764dbcd10721e2e > > compiler: Debian clang version 11.0.1-2 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11be6bd1d00000 > > Hi syz people and x86 people- > > I entirely believe that this bug is real and that syzbot bisected it > correctly, but I'm puzzled by the reproducer. It says: > > ptrace$setregs(0xd, r0, 0x0, &(0x7f0000000080)) > > I would really, really expect this to result from PTRACE_SETREGSET or > PTRACE_SETFPREGS, but this is PTRACE_SETREGS. > > Am I missing something really obvious here?
Hi Andy,
Sometimes syzkaller uses data format from one syscall variant, but actually invokes another. But here it does _not_ seem to be the case: 0xd is actually PTRACE_SETREGS. And the other ptrace calls in the reproducer are PTRACE_SEIZE and PTRACE_SINGLESTEP. So I would assume somehow it happened with PTRACE_SETREGS. Is there any indication from hardware as to what's wrong with fpregs?
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